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Updated 8:30 AM June 1, 2004



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  The buzz about cicadas
Noisy bugs emerge after 17 years underground

Bug-eyed and buzzing, hordes of periodical cicadas are appearing in Michigan and a handful of other states. After developing underground for 17 years, the harmless but noisy insects are emerging by the millions this month.

The adults will spend about six weeks engaged in raucous reproductive behavior, and then they'll be gone, leaving millions of tiny offspring behind to burrow into the soil and start the 17-year cycle all over again. This dramatic phenomenon occurs only in the eastern United States.

The mass emergences have fascinated professor emeritus Thomas Moore for half a century—ever since he first witnessed this particular brood of bugs arising en masse in 1953. He's so attuned to their choruses, he can estimate their numbers and stage of courtship as he drives through an emergence area with his car windows down. And after studying them so long, he's the go-to guy for anything you'd ever want to know about cicadas—both the 17-year kind and those that stay underground for shorter periods.

The reddish-orange and black insects that are blanketing trees and shrubs in May and June belong to Brood X (10) of periodical cicadas, Moore says. A different brood of periodical cicadas emerges somewhere in the country most years, but Brood X is the largest, with a patchwork distribution that ranges from Long Island, N.Y., south to Georgia, north to Michigan and west to Illinois.

The critters take a full 17 years to mature from ant-sized nymph to peanut-sized adult. During their years of subterranean seclusion, the juvenile forms suck juices from small roots, shedding their skins four times as they grow. When their time in the sun finally comes, the nymphs tunnel to the surface and wait for the soil to warm to about 64 degrees F before venturing out.

"They're amazingly synchronized," with hundreds of thousands to more than a million per acre appearing almost simultaneously at night in some areas, Moore says. In Michigan, they'll be most abundant in Washtenaw and Lenawee counties, but sizeable congregations also are expected in the Bloomfield area of Oakland County and around Hamburg in Livingston County.

After hauling themselves out of the ground and using their clawed front legs to climb up tree trunks, the nymphs balloon out of their skins one last time to become adults. Their ghostly shed skins, looking a little like fried pork rinds with legs, often are found clinging to tree trunks or scattered on the ground. Within a day or two, the adult males begin their cacophonous chorusing, producing sound by vibrating abdominal drums called timbals. At 100 decibels or more at a distance of one inch, the racket is among nature's loudest sounds, rivaling a jet airplane at takeoff.

The sudden flush of insects is a feast for wildlife. "Everything that can eat them, will," Moore says. That includes fishes, birds, squirrels, chipmunks, raccoons, foxes, skunks, many other insects—and, on occasion, Moore, who says they taste like popcorn when fried in butter.

Females that avoid being eaten long enough to mate and lay eggs deposit hundreds of them in living twigs about as big around as pencils. An abundance of eggs can cause the branch tips to break and terminal leaves to die, but that usually doesn't hurt healthy, mature trees. (Small trees and shrubs can be protected by draping them with cheesecloth or light screening.)

Overall, cicadas may be good for forests, which may experience a growth spurt the year after an emergence, Moore says.

As for their effects on people, there's nothing to fear. Though a few freak incidents have been reported—cicadas accidentally flying into yawning mouths or kids trying to bat bugs on the wing and hitting each other instead—the docile insects don't bite or sting.

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